U.S. patent number 10,700,166 [Application Number 13/904,315] was granted by the patent office on 2020-06-30 for nozzle cleaning device, nozzle cleaning method, and substrate processing apparatus.
This patent grant is currently assigned to TOKYO ELECTRON LIMITED. The grantee listed for this patent is Tokyo Electron Limited. Invention is credited to Shinya Ishikawa, Yoshihiro Kai, Yuji Kamikawa, Shuichi Nagamine, Naoki Shindo.
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United States Patent |
10,700,166 |
Kai , et al. |
June 30, 2020 |
Nozzle cleaning device, nozzle cleaning method, and substrate
processing apparatus
Abstract
A nozzle cleaning device is capable of uniformly cleaning a
nozzle from a front end of the nozzle to an upper part thereof. The
nozzle cleaning device includes a storage tank, a liquid
discharging portion and an overflow discharging portion. The
storage tank has a cylindrical inner peripheral surface and is
configured to store therein a cleaning liquid that cleans a nozzle
used in a substrate process. The liquid discharging portion is
configured to discharge the cleaning liquid into the storage tank
toward a position eccentric with respect to a central axis of the
cylindrical inner peripheral surface to store the cleaning liquid
within the storage tank and configured to form a vortex flow of the
cleaning liquid revolving within the storage tank. The overflow
discharging portion is configured to discharge the cleaning liquid
that overflows the storage tank.
Inventors: |
Kai; Yoshihiro (Koshi,
JP), Ishikawa; Shinya (Koshi, JP),
Kamikawa; Yuji (Koshi, JP), Nagamine; Shuichi
(Koshi, JP), Shindo; Naoki (Nirasaki, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
Tokyo Electron Limited |
Tokyo |
N/A |
JP |
|
|
Assignee: |
TOKYO ELECTRON LIMITED (Tokyo,
JP)
|
Family
ID: |
49849809 |
Appl.
No.: |
13/904,315 |
Filed: |
May 29, 2013 |
Prior Publication Data
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|
|
Document
Identifier |
Publication Date |
|
US 20130319470 A1 |
Dec 5, 2013 |
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Foreign Application Priority Data
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May 31, 2012 [JP] |
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2012-125173 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B08B
9/0321 (20130101); B05B 15/555 (20180201); H01L
29/1608 (20130101); H01L 29/7813 (20130101); B05B
15/557 (20180201); B08B 3/102 (20130101); B08B
9/0328 (20130101); H01L 21/67051 (20130101); B05B
1/36 (20130101) |
Current International
Class: |
B08B
9/032 (20060101); H01L 29/16 (20060101); B05B
15/55 (20180101); B05B 15/555 (20180101); B08B
3/10 (20060101); H01L 21/67 (20060101); H01L
29/78 (20060101); B05B 1/36 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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05-166715 |
|
Jul 1993 |
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JP |
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H08-192083 |
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Jul 1996 |
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JP |
|
H10-258249 |
|
Sep 1998 |
|
JP |
|
2000-167469 |
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Jun 2000 |
|
JP |
|
2006-263535 |
|
Oct 2006 |
|
JP |
|
2007-258462 |
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Apr 2007 |
|
JP |
|
2007-258462 |
|
Oct 2007 |
|
JP |
|
2007-317706 |
|
Dec 2007 |
|
JP |
|
2010-062352 |
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Mar 2010 |
|
JP |
|
20070036865 |
|
Apr 2007 |
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KR |
|
100895030 |
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Apr 2009 |
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KR |
|
20110058286 |
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Jun 2011 |
|
KR |
|
Other References
KR20070036865--Machine Translation, Apr. 2007. cited by examiner
.
KR100895030--Machine Translation, Apr. 2009. cited by examiner
.
JP2006263535--Machine Translation (Year: 2006). cited by examiner
.
KR20110058286--Machine Translation (Year: 2011). cited by
examiner.
|
Primary Examiner: Lorenzi; Marc
Attorney, Agent or Firm: Pearne & Gordon LLP
Claims
What is claimed is:
1. A nozzle cleaning device comprising: a storage tank, having a
cylindrical inner peripheral surface and an outer wall of a first
height, said storage tank being configured to store a cleaning
liquid and immerse a nozzle therein; a liquid discharging portion
configured to discharge the cleaning liquid into the storage tank
toward a position eccentric with respect to a central axis of the
cylindrical inner peripheral surface within the storage tank and
configured to discharge the cleaning liquid tangentially into
contact with the cylindrical inner peripheral surface to form a
vortex flow of the cleaning liquid revolving within the storage
tank; a cleaning liquid supply source connected to the liquid
discharging portion and configured to supply the cleaning liquid to
the liquid discharging portion; an overflow discharging portion
separated from the storage tank by a barrier of a second height,
said second height being lower than said first height, said
overflow discharge portion being configured to discharge the
cleaning liquid that overflows out of the storage tank from a top
surface of the storage tank over said barrier; a gas supply source;
and a gas injecting portion configured to inject a gas, comprising:
at least one first injecting portion that is located at a vertical
position higher than the liquid discharging portion and is
configured to inject the gas in a downwardly inclined direction;
and at least one second injecting portion that is located at a
vertical position equal to the liquid discharging portion and is
configured to inject the gas in a horizontal direction, wherein an
upstream side of the at least one second injecting portion is in
fluid communication with only the gas supply source from among the
gas supply source and the cleaning liquid supply source, wherein
the storage tank has a funnel-shaped bottom surface directly
connected to the cylindrical inner peripheral surface, and a vertex
of the funnel-shaped bottom surface is located at a position
eccentric with respect to the central axis of the cylindrical inner
peripheral surface, and a discharge opening through which the
cleaning liquid is discharged is arranged at the vertex.
2. The nozzle cleaning device of claim 1, wherein the at least one
first injecting portion and the at least one second injecting
portion are plural in number.
3. The nozzle cleaning device of claim 2, wherein, in the first
injecting portions, one-side first injecting portions whose
injection openings are arranged at one side of the nozzle and
another-side first injecting portions whose injection openings are
arranged at another side of the nozzle are configured to inject the
gas in parallel to each other while the gas injected from the
one-side first injecting portions and the gas injected from the
another-side first injecting portions do not collide with each
other, when viewed from the top.
4. The nozzle cleaning device of claim 1, further comprising: an
air intake unit provided above the storage tank and configured to
suction therein the gas in an amount equal to or greater than that
of the gas injected from the gas injecting portion.
5. The nozzle cleaning device of claim 1, wherein the cleaning
liquid includes a deionized water heated at a predetermined
temperature.
6. A substrate processing apparatus comprising: a nozzle configured
to discharge a fluid toward a substrate; an arm configured to
support and move the nozzle; and the nozzle cleaning device of
claim 1.
7. The substrate processing apparatus of claim 6, further
comprising: a flow rate controller configured to control a flow
rate of the gas injected from the gas injecting portion; and a
control unit configured to control the flow rate controller,
wherein the control unit controls the flow rate controller to allow
the gas injecting portion to inject the gas at a different flow
rate between when performing a cleaning process of the nozzle and
when performing a drying process of the nozzle.
8. The substrate processing apparatus of claim 6, further
comprising: a nozzle standby unit, having an accommodating portion
that accommodates therein the nozzle, configured to allow the
nozzle to standby while accommodating the nozzle in the
accommodating portion, the nozzle standby unit being disposed to be
adjacent to the nozzle cleaning device.
9. The nozzle cleaning device of claim 1, wherein the overflow
discharging portion includes a vertical flow path extended in a
vertical direction within the nozzle cleaning device, and the
cleaning liquid that has been overflowed from the top surface of
the storage tank is discharged to outside of the nozzle cleaning
device via the vertical flow path.
10. The nozzle cleaning device of claim 9, further comprising: a
liquid collecting portion provided below the vertical flow path and
configured to collect the cleaning liquid introduced from a
discharge opening provided at a bottom of the storage tank and the
cleaning liquid introduced from the vertical flow path.
Description
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the benefit of Japanese Patent Application
No. 2012-125273 filed on May 31, 2012, the entire disclosures of
which are incorporated herein by reference.
FIELD OF THE INVENTION
The present disclosure relates to a nozzle cleaning device, a
nozzle cleaning method, and a substrate processing apparatus.
BACKGROUND OF THE INVENTION
Conventionally, there has been known a substrate processing
apparatus that processes a substrate, such as a semiconductor wafer
or a glass substrate, by supplying a processing liquid through a
nozzle.
The processing liquid may adhere to the nozzle and may remain at
the nozzle as a cohesive material. If a substrate process is
performed while such a cohesive material adheres to the nozzle, the
cohesive material adhering to the nozzle may be scattered on the
substrate, so that the substrate is damaged. Therefore, such a
substrate processing apparatus may include a nozzle cleaning device
configured to clean the nozzle with a cleaning liquid to remove the
cohesive material adhering to the nozzle.
By way of example, Patent Document 1 describes a nozzle cleaning
device configured to inject a cleaning liquid to a nozzle from one
side of the nozzle to remove a cohesive material adhering to the
nozzle.
Further, Patent Document 2 describes a nozzle cleaning device that
includes a cleaning chamber configured to accommodate a nozzle and
is configured to supply a cleaning liquid along an inner peripheral
surface of the cleaning chamber and form a vortex-shaped flow of
the cleaning liquid around a front end of the nozzle to clean the
front end of the nozzle.
Patent Document 1: Japanese Patent Laid-open Publication No.
2007-258462
Patent Document 2: Japanese Patent Laid-open Publication No.
2007-317706
However, if the cleaning liquid is injected as described in Patent
Document 1, the nozzle may not be cleaned uniformly. In particular,
if the cleaning liquid is injected from one side of the nozzle as
described in Patent Document 1, the other side of the nozzle cannot
be cleaned sufficiently.
Further, in accordance with the method as described in Patent
Document 2, an upper part of the nozzle may not be cleaned. This is
because if the upper part of the nozzle is cleaned by the cleaning
liquid stored in the cleaning chamber, the cleaning liquid may
overflow a storage tank.
BRIEF SUMMARY OF THE INVENTION
The present disclosure provides a nozzle cleaning device, a nozzle
cleaning method, and a substrate processing apparatus capable of
uniformly cleaning a nozzle from a front end of the nozzle to an
upper part thereof.
In accordance with one aspect of the illustrative embodiments,
there is provided a nozzle cleaning device including a storage tank
having a cylindrical inner peripheral surface and configured to
store therein a cleaning liquid that cleans a nozzle used in a
substrate process; a liquid discharging portion configured to
discharge the cleaning liquid into the storage tank toward a
position eccentric with respect to a central axis of the
cylindrical inner peripheral surface to store the cleaning liquid
within the storage tank and configured to form a vortex flow of the
cleaning liquid revolving within the storage tank; and an overflow
discharging portion configured to discharge the cleaning liquid
that overflows the storage tank.
Further, in accordance with another aspect of the illustrative
embodiments, there is provided a nozzle cleaning method that
includes inserting at least one nozzle used in substrate processes
into a storage tank having a cylindrical inner peripheral surface;
cleaning the at least one nozzle by discharging a cleaning liquid
into the storage tank toward a position eccentric with respect to a
central axis of the cylindrical inner peripheral surface of the
storage tank to store the cleaning liquid in the storage tank and
to immerse the at least one nozzle therein; and by forming a vortex
flow that revolves within the storage tank; and allowing the
cleaning liquid to overflow the storage tank and discharging the
overflowed cleaning liquid through an overflow discharging
portion.
Furthermore, in accordance with still another aspect of the
illustrative embodiments, there is provided a substrate processing
apparatus including a nozzle configured to discharge a fluid toward
a substrate; an arm configured to support and move the nozzle; and
the nozzle cleaning device described above.
In accordance with the illustrative embodiments, it is possible to
uniformly clean a nozzle from a front end of the nozzle to an upper
part thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
Non-limiting and non-exhaustive embodiments will be described in
conjunction with the accompanying drawings. Understanding that
these drawings depict only several embodiments in accordance with
the disclosure and are, therefore, not to be intended to limit its
scope, the disclosure will be described with specificity and detail
through use of the accompanying drawings, in which:
FIG. 1 illustrates a configuration of a substrate processing system
in accordance with a first illustrative embodiment;
FIG. 2 is a schematic plane view of a configuration of a substrate
processing apparatus in accordance with the first illustrative
embodiment;
FIG. 3 is a schematic perspective view of a configuration of a
discharging device;
FIG. 4 is a schematic perspective view of a configuration of a
nozzle cleaning device;
FIG. 5 is a schematic side cross sectional view of a configuration
of a second cleaning unit;
FIG. 6 is a schematic plane cross sectional view illustrating an
arrangement of a liquid discharging portion;
FIG. 7 is a schematic side cross sectional view illustrating
directions of a gas injected by an upper injecting portion and a
lower injecting portion;
FIG. 8A is a schematic plane cross sectional view illustrating an
arrangement of the upper injecting portions;
FIG. 8B is a schematic plane cross sectional view illustrating an
arrangement of the lower injecting portions;
FIG. 9 is a schematic plane cross sectional view illustrating
another arrangement example of upper injecting portions;
FIG. 10A is a schematic side cross sectional view illustrating an
operation example of a nozzle cleaning process;
FIG. 10B is a schematic side cross sectional view illustrating an
operation example of a nozzle cleaning process;
FIG. 10C is a schematic side cross sectional view illustrating an
operation example of a nozzle cleaning process;
FIG. 10D is a schematic side cross sectional view illustrating an
operation example of a nozzle cleaning process;
FIG. 10E is a schematic side cross sectional view illustrating an
operation example of a nozzle cleaning process;
FIG. 11 is a schematic side cross sectional view illustrating a
configuration of a substrate processing apparatus;
FIG. 12A is a schematic side cross sectional view illustrating an
operation example of a substrate process;
FIG. 12B is a schematic side cross sectional view illustrating an
operation example of a substrate process;
FIG. 13 shows a timing for performing a substrate process and a
nozzle cleaning process;
FIG. 14 is a schematic perspective view of a configuration of a
nozzle cleaning device in accordance with a second illustrative
embodiment;
FIG. 15A is a schematic side cross sectional view of a
configuration of a storage tank in accordance with a third
illustrative embodiment;
FIG. 15B is a schematic side cross sectional view of another
configuration (a first modification example) of the storage tank in
accordance with the third illustrative embodiment;
FIG. 16A is a schematic plane cross sectional view of still another
configuration (a second modification example) of the storage tank
in accordance with the third illustrative embodiment;
FIG. 16B is a schematic side cross sectional view of the storage
tank depicted in FIG. 16A; and
FIG. 16C is a schematic plane cross sectional view of still another
configuration (a third modification example) of the storage tank in
accordance with the third illustrative embodiment.
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, illustrative embodiments of a nozzle cleaning device,
a nozzle cleaning method, and a substrate processing apparatus will
be described in detail with reference to the accompanying drawings
so that inventive concept may be readily implemented by those
skilled in the art. However, it is to be noted that the present
disclosure is not limited to the illustrative embodiments but can
be realized in various other ways.
First Illustrative Embodiment
<Configuration of Substrate Processing System>
A configuration of substrate processing system in accordance with a
first illustrative embodiment will be explained with reference to
FIG. 1. FIG. 1 illustrates the configuration of the substrate
processing system in accordance with the first illustrative
embodiment.
Hereinafter, an X-axis, a Y-axis, and a Z-axis orthogonal to one
another are defined, and a positive direction of the Z-axis is set
as a upwardly vertical direction for clearness in positional
relationships. Further, hereinafter, a negative direction of the
X-axis is set as a forward direction of the substrate processing
system and a positive direction of the X-axis is set as a backward
direction of the substrate processing system.
As depicted in FIG. 1, a substrate processing system 100 includes a
substrate loading/unloading unit 2, a substrate transferring unit
3, and a substrate processing unit 4. The substrate
loading/unloading unit 2, the substrate transferring unit 3, and
the substrate processing unit 4 are connected in sequence from the
forward direction of the substrate processing system 100 to the
backward direction thereof.
The substrate loading/unloading unit 2 is configured to load/unload
multiple (for example, about 25) substrates W into/from a carrier
2a. In the substrate loading/unloading unit 2, for example, four
carriers 2a may be arranged side by side while adhering to a front
wall 3a of the substrate transferring unit 3.
The substrate transferring unit 3 is positioned at a back of the
substrate loading/unloading unit 2, and includes therein a
substrate transferring device 3b and a substrate transiting table
3c. The substrate transferring unit 3 transfers a substrate W
between the carrier 2a arranged in the substrate loading/unloading
unit 2 and the substrate transiting table 3c by using the substrate
transferring device 3b.
The substrate processing unit 4 is positioned at a back of the
substrate transferring unit 3. The substrate processing unit 4
includes a substrate transferring device 4a at a central portion
thereof, and both sides of the substrate transferring device 4a
respectively include multiple (herein, about 6) substrate
processing apparatuses 1a to 1l arranged side by side in the
forward/backward direction (in a direction parallel to the
X-axis).
The substrate transferring device 4a is configured to transfer each
substrate W between the substrate transiting table 3c of the
substrate transferring unit 3 and the respective substrate
processing apparatuses 1a to 1l, and each of the substrate
processing apparatuses 1a to 1l process the substrates W one by
one.
<Configuration of Substrate Processing Apparatus>
Hereinafter, a configuration of a substrate processing apparatus in
accordance with the first illustrative embodiment will be explained
with reference to FIG. 2. FIG. 2 is a schematic plane view of the
configuration of the substrate processing apparatus in accordance
with the first illustrative embodiment.
As depicted in FIG. 2, a substrate processing apparatus 1 is
configured to process a substrate W by using various kinds of
processing liquids discharged through a nozzle. To be specific, the
substrate processing apparatus includes a substrate holding unit
20, processing liquid supplying units 30A and 30B, nozzle standby
units 40A and 40B, and a nozzle cleaning device 50 within a
processing chamber 10.
The substrate holding unit 20 includes a rotation holding device 21
configured to hold the substrate W to be rotated and a processing
liquid collecting device 22 provided to surround the rotation
holding device 21. The substrate holding unit 20 is configured to
rotate the substrate W by using the rotation holding device 21 and
to collect a processing liquid scattered to an outside of the
substrate W due to a centrifugal force caused by the rotation of
the substrate W through the processing liquid collecting device
22.
Further, the rotation holding device 21 is configured to hold the
substrate W in a substantially horizontal manner and to rotate the
held substrate W around a vertical axis.
The processing liquid supplying units 30A and 30B are configured to
supply a processing liquid from above the substrate W held by the
substrate holding unit 20 toward the substrate W. The processing
liquid supplying units 30A and 30B include discharging devices 31A
and 31B configured to discharge a processing liquid, arms 32A and
32B configured to horizontally support the discharging devices 31A
and 31B, and rotation elevating devices 33A and 33B configured to
rotate and elevate the arms 32A and 32B, respectively.
Further, the arms 32A and 32B and the rotation elevating devices
33A and 33B are provided as an example for supporting and moving a
nozzle.
The discharging devices 31A and 31B include nozzles configured to
discharge a processing liquid toward the substrate W. To be
specific, the substrate processing apparatus 1 includes a first
nozzle configured to discharge a SPM (Sulfuric Acid Hydrogen
Peroxide Mixture), a second nozzle configured to discharge a SC1,
and a third nozzle configured to mix a processing liquid with a gas
and discharge the mixture in a misty state. The first nozzle and
the third nozzle are provided in the discharging device 31A, and
the second nozzle is provided in the discharging device 31B.
The SPM is a mixed solution of H.sub.2SO.sub.4 and H.sub.2O.sub.2,
and the SC1 is a mixed solution of ammonia water, hydrogen peroxide
water, and water.
Herein, a configuration of the discharging device 31A including the
first nozzle and the third nozzle will be explained with reference
to FIG. 3. FIG. 3 is a schematic perspective view of the
configuration of the discharging device 31A.
As depicted in FIG. 3, the discharging device 31A includes a base
portion 311, a first nozzle 312, and a third nozzle 313.
The base portion 311 is connected to a front end of the arm 32A.
The first nozzle 312 and the third nozzle 313 are provided to be
adjacent to each other at a lower front end of the base portion
311.
The first nozzle 312 is connected to a non-illustrated SPM supply
source via a valve 314 and configured to discharge a SPM supplied
from the SPM supply source via the valve 314 in a vertically
downward direction.
The third nozzle 313 is a dual fluid nozzle configured to mix a
liquid with a gas and discharge the mixture. The third nozzle 313
includes a first discharge opening connected to a non-illustrated
processing liquid supply source via a valve 315 and a second
discharge opening connected to a non-illustrated gas supply source
via a valve 316.
The third nozzle 313 discharges a processing liquid through the
first discharge opening and discharges a gas (N.sub.2) through the
second discharge opening. Thus, the processing liquid and the gas
are mixed outside the third nozzle 313 to form a processing liquid
in a misty state. As a result, the processing liquid in a misty
state is supplied to the substrate W.
The first nozzle 312 and the third nozzle 313 are connected to a
non-illustrated flow rate controller. The flow rate controller is
configured to control a flow rate of the processing liquid and the
gas discharged through the first nozzle 312 and the third nozzle
313. The flow rate controller and the valves 314 to 316 are
controlled by a control unit to be described later.
As described above, the discharging device 31A includes both the
first nozzle 312 and the third nozzle 313.
Here, a cohesive material formed from the dried and solidified SPM
may adhere to the first nozzle 312 configured to discharge the SPM.
Further, in the discharging device 31A, such a cohesive material
may adhere not only to the first nozzle 312 but also to the third
nozzle 313 adjacent to the first nozzle 312. If a substrate process
is performed while such a cohesive material adheres to the first
nozzle 312 or the third nozzle 313, the cohesive material may be
scattered on the substrate W, so that the substrate W may be
damaged.
Meanwhile, the substrate processing apparatus 1 in accordance with
the first illustrative embodiment can remove the cohesive material
adhering to the first nozzle 312 and the third nozzle 313 by
cleaning the first nozzle 312 and the third nozzle 313 with the
nozzle cleaning device 50. The nozzle cleaning device 50 allows a
cleaning liquid to overflow, so that the nozzle is immersed to be
cleaned. As compared with the conventional cleaning device, the
nozzle cleaning device 50 can clean the nozzle from a front end of
the nozzle to an upper part thereof. Details thereof will be
explained later.
The discharging device 31B includes a base portion connected to the
arm 32B and a second nozzle provided at a lower front end of the
base portion. The second nozzle is connected to a non-illustrated
SC1 supply source via a non-illustrated valve and configured to
discharge a SC1 supplied from the SC1 supply source in a vertically
downward direction.
The nozzle standby units 40A and 40B are provided at standby
positions of the processing liquid supplying units 30A and 30B,
respectively. Further, the nozzle standby units 40A and 40B include
accommodating portions configured to accommodate the nozzles of the
processing liquid supplying units 30A and 30B, respectively.
To be specific, the nozzle standby unit 40A includes a first
accommodating portion 41 for accommodating the first nozzle 312 and
a second accommodating portion 42 for accommodating the third
nozzle 313. The nozzle standby unit 40B includes an accommodating
portion (not illustrated) for accommodating the second nozzle. The
processing liquid supplying units 30A and 30B allow the nozzles to
be accommodated in the accommodating portions of the nozzle standby
units 40A and 40B and to stand by while appropriately discharging a
processing liquid through the nozzles in order to prevent the
processing liquid from being deteriorated.
The nozzle cleaning device 50 is configured to clean the first
nozzle 312 and the third nozzle 313 of the processing liquid
supplying unit 30A, and is disposed to be adjacent to the nozzle
standby unit 40A.
<Configuration of Nozzle Cleaning Device>
Hereinafter, a configuration of the nozzle cleaning device 50 will
be explained with reference to FIG. 4. FIG. 4 is a schematic
perspective view of the configuration of the nozzle cleaning device
50.
As depicted in FIG. 4, the nozzle cleaning device 50 includes a
first cleaning unit 50A configured to clean the first nozzle 312
and a second cleaning unit 50B configured to clean the third nozzle
313. Further, the nozzle cleaning device 50 is configured to clean
the first nozzle 312 and the third nozzle 313 individually or
simultaneously.
The nozzle standby unit 40A includes a first drain portion 43
configured to discharge the SPM stored in the first accommodating
portion 41 to the outside, and a second drain portion 44 configured
to discharge the processing liquid stored in the second
accommodating portion 42 to the outside. The nozzle cleaning device
50 is connected to the nozzle standby unit 40A, and the cleaning
liquid used for cleaning the nozzles in the nozzle cleaning device
50 is discharged through the first drain portion 43 and the second
drain portion 44 of the nozzle standby unit 40A.
Hereinafter, a configuration of the second cleaning unit 50B
configured to clean the third nozzle 313 will be explained with
reference to FIG. 5. FIG. 5 is a schematic side cross sectional
view of the configuration of the second cleaning unit 50B. Since
the first cleaning unit 50A has substantially the same
configuration as that of the second cleaning unit 50B, only the
configuration of the second cleaning unit 50B will be explained and
an explanation of the first cleaning unit 50A will be omitted.
As depicted in FIG. 5, the second cleaning unit 50B includes a
storage tank 51, a liquid discharging portion 52, a gas injecting
portion 53, an overflow discharging portion 54, and a liquid
collecting portion 55.
The storage tank 51 has a cylindrical inner peripheral surface 61
and stores a cleaning liquid for cleaning the third nozzle 313. The
cleaning liquid is, for example, HDIW. The HDIW is high-temperature
deionized water heated at a preset temperature (from about
45.degree. C. to about 80.degree. C.) higher than the room
temperature (for example, about 20.degree. C.). By using the HDIW
as the cleaning liquid, it is possible to perform a cleaning
efficiently as compared with a case where the room-temperature
deionized water CDIW is used.
Further, the storage tank 51 has a funnel-shaped bottom surface 62
connected to the cylindrical inner peripheral surface 61. At a
vertex of the bottom surface 62, there is formed a discharge
opening 63 that connects the storage tank 51 to the liquid
collecting portion 55. The cleaning liquid stored in the storage
tank 51 is collected in the liquid collecting portion 55 through
the discharge opening 63.
Thus, since the bottom surface 62 of the storage tank 51 has a
funnel shape, the cleaning liquid stored in the storage tank 51 can
be discharged efficiently through the discharge opening 63.
In the first illustrative embodiment, the vertex of the
funnel-shaped bottom surface 62 is positioned at the substantially
same axis as a central axis of the inner peripheral surface 61 of
the storage tank 51. However, the "funnel shape" is not limited to
thereto and may allow the vertex of the funnel to be positioned
eccentrically with respect to the central axis of the inner
peripheral surface of the storage tank 51. Details thereof will be
explained in a third illustrative embodiment.
The liquid discharging portion 52 is configured to discharge the
cleaning liquid into the storage tank 51. To be specific, the
liquid discharging portion 52 is connected to a supply source of
the HDIW as the cleaning liquid via a valve 64 and discharges the
HDIW supplied from the HDIW supply source via the valve 64 into the
storage tank 51. Opening and closing of the valve 64 is controlled
by the control unit to be described later.
The liquid discharging portion 52 is configured to supply the
cleaning liquid in an amount more than the cleaning liquid
discharged through the discharge opening 63 of the storage tank 51.
Thus, the cleaning liquid is stored within the storage tank 51.
Further, the liquid discharging portion 52 discharges the cleaning
liquid within the storage tank 51 toward a position eccentric with
respect to the central axis of the inner peripheral surface 61 of
the storage tank 51 to form a vortex flow of the cleaning liquid
within the storage tank 51. Hereinafter, an arrangement of the
liquid discharging portion 52 will be explained with reference to
FIG. 6. FIG. 6 is a schematic plane cross sectional view
illustrating the arrangement of the liquid discharging portion
52.
As depicted in FIG. 6, the liquid discharging portion 52 includes a
discharge opening 52a formed along a tangential direction of the
inner peripheral surface 61 of the storage tank 51 and a flow path
52b communicating with the discharge opening 52a. The cleaning
liquid discharged from the liquid discharging portion 52 flows
along the inner peripheral surface 61 of the storage tank 51. Thus,
a vortex flow of the cleaning liquid is formed within the storage
tank 51.
As described above, since the liquid discharging portion 52
discharges the cleaning liquid along the inner peripheral surface
61 of the storage tank 51, the cleaning liquid can be stored within
the storage tank 51 and the vortex flow revolving within the
storage tank 51 can be formed.
The second cleaning unit 50B immerses and cleans the third nozzle
313 by using the cleaning liquid stored within the storage tank 51.
Thus, the second cleaning unit 50B can clean the third nozzle 313,
inserted into the storage tank 51, from the front end of the nozzle
to the upper part thereof. Further, the second cleaning unit 50B
forms a vortex flow within the storage tank 51, so that a cleaning
effect of the third nozzle 313 can be increased.
Furthermore, the second cleaning unit 50B allows the cleaning
liquid within the storage tank 51 to overflow, so that the third
nozzle 313 is immersed to be cleaned as described later. Thus, a
contaminant such as the cohesive material removed from the third
nozzle 313 can be discharged to the outside of the storage tank 51,
and the vortex flow can be formed continuously within the storage
tank 51.
In order to form a vortex flow within the storage tank 51, the
cleaning liquid discharged from the liquid discharging portion 52
just needs to resultingly flow along the inner peripheral surface
61 of the storage tank 51, but the liquid discharging portion 52
does not need to discharge the cleaning liquid along the inner
peripheral surface 61 of the storage tank 51. That is, the liquid
discharging portion 52 just needs to discharge the cleaning liquid
within the storage tank 51 toward a position eccentric with respect
to the central axis of the inner peripheral surface 61 of the
storage tank 51.
Further, the liquid discharging portion 52 is located at a vertical
position substantially equal to a front end surface of the third
nozzle 313 inserted into the storage tank 51 as depicted in FIG. 5.
Thus, the liquid discharging portion 52 can form a vortex flow near
the front end surface of the third nozzle 313. Therefore, it is
possible to effectively clean the front end surface of the third
nozzle 313 to which the cohesive material of SPM may easily
adhere.
The gas injecting portion 53 is configured to inject a gas
(N.sub.2) into the storage tank 51. The gas injecting portion 53
includes an upper injecting portion 53A (corresponding to a first
injecting portion) and a lower injecting portion 53B (corresponding
to a second injecting portion).
Each of the upper injecting portion 53A and the lower injecting
portion 53B includes an injection opening formed at the inner
peripheral surface 61 of the storage tank 51 and a flow path
communicating with the injection opening. The flow path of the
upper injecting portion 53A and the flow path of the lower
injecting portion 53B communicate with each other, and are
connected to a non-illustrated gas supply source. Further, a line
connecting the upper injecting portion 53A and the lower injecting
portion 53B to the gas supply source includes a first valve 65 and
a second valve 66 arranged in parallel with each other.
The upper injecting portion 53A and the lower injecting portion 53B
inject the gas (N.sub.2) supplied from the non-illustrated gas
supply source via the first valve 65 or the second valve 66 into
the storage tank 51, so that the cleaning liquid remaining on a
surface of the third nozzle 313 after the cleaning of the nozzle
can be removed. Opening and closing of the first valve 65 and the
second valve 66 is controlled by the control unit to be described
later.
Hereinafter, a direction of a gas injected by each of the upper
injecting portion 53A and the lower injecting portion 53B will be
explained with reference to FIG. 7. FIG. 7 is a schematic side
cross sectional view illustrating directions of a gas injected by
the upper injecting portion 53A and the lower injecting portion
53B.
As depicted in FIG. 7, the upper injecting portion 53A is located
at a vertical position higher than the front end surface of the
third nozzle 313 inserted into the storage tank 51, and is
configured to inject the gas supplied from the gas supply source in
a downwardly inclined direction. Thus, the upper injecting portion
53A blows away the cleaning liquid remaining at an outer peripheral
surface of the third nozzle 313 to dry the third nozzle 313.
Since the upper injecting portion 53A injects the gas in the
downwardly inclined direction, it is possible to prevent the
cleaning liquid removed from the third nozzle 313 from being
scattered to the outside of the storage tank 51.
The lower injecting portion 53B is located at a vertical position
substantially equal to the front end surface of the third nozzle
313 inserted into the storage tank 51, and is configured to inject
the gas in a substantially horizontal direction toward the front
end surface of the third nozzle 313. Thus, the lower injecting
portion 53B mainly dries the front end surface of the third nozzle
313 where the cleaning liquid easily remains.
The gas injecting portion 53 includes multiple upper injecting
portions 53A and multiple lower injecting portions 53B.
Hereinafter, an arrangement of the upper injecting portions 53A and
an arrangement of the lower injecting portions 53B will be
explained with reference to FIGS. 8A and 8B. FIG. 8A is a schematic
plane cross sectional view illustrating an arrangement of the upper
injecting portions 53A, and FIG. 8B is a schematic plane cross
sectional view illustrating an arrangement of the lower injecting
portions 53B.
As depicted in FIG. 8A, the gas injecting portion 53 includes ten
upper injecting portions 53Aa to 53Aj. Among them, the upper
injecting portions 53Aa to 53Ae are arranged in parallel to one
another at one side of the inner peripheral surface 61 of the
storage tank 51, and are configured to inject the gas toward the
other side of the inner peripheral surface 61 of the storage tank
51. Further, the other upper injecting portions 53Af to 53Aj are
arranged in parallel to one another at the other side of the inner
peripheral surface 61 of the storage tank 51, and are configured to
inject the gas toward the one side of the inner peripheral surface
61 of the storage tank 51.
As described above, the multiple upper injecting portions 53Aa to
53Aj inject the gas (N.sub.2) toward the third nozzle 313 from the
both sides of the third nozzle 313. Thus, the gas can be supplied
to substantially the entire outer peripheral surface of the third
nozzle 313, so that the outer peripheral surface of the third
nozzle 313 can be dried more effectively.
FIG. 8A illustrates an example where the upper injecting portions
53Aa to 53Ae and the upper injecting portions 53Af to 53Aj inject
the gas in a direction parallel to their arrangement direction
(X-axis direction), i.e., in a direction facing each other.
However, the present disclosure is not limited thereto. The upper
injecting portions arranged at the one side of the third nozzle 313
and the upper injecting portions arranged at the other side of the
third nozzle 313 may inject the gas in an inclined direction with
respect to their arrangement direction. Details thereof will be
explained with reference to FIG. 9. FIG. 9 is a schematic plane
cross sectional view illustrating another arrangement example of
upper injecting portions.
As depicted in FIG. 9, four upper injecting portions 53Aa' to 53Ad'
are arranged at the one side of the third nozzle 313 in a storage
tank 51' and four upper injecting portions 53Ae' to 53Ah' are
arranged at the other side of the third nozzle 313. Hereinafter,
the upper injecting portions 53Aa' to 53Ad' will be referred to as
"one-side upper injecting portions 53Aa' to 53Ad'" and the upper
injecting portions 53Ae' to 53Ah' will be referred to as
"other-side upper injecting portions 53Ae' to 53Ah'".
The one-side upper injecting portions 53Aa' to 53Ad' and the
other-side upper injecting portions 53Ae' to 53Ah' are arranged
such that their injection openings are parallel to the X-axis
direction. To be specific, the injection openings of the one-side
upper injecting portions 53Aa' to 53Ad' are arranged toward the
positive direction of the X-axis of the third nozzle 313 and the
injection openings of the other-side upper injecting portions 53Ae'
to 53Ah' are arranged toward the negative direction of the X-axis
of the third nozzle 313.
When viewed from the top, the one-side upper injecting portions
53Aa' to 53Ad' and the other-side upper injecting portions 53Ae' to
53Ah' injects the gas in an inclined direction with respect to the
arrangement direction of their injection openings (i.e., X-axis
direction).
To be specific, an inclination of the direction of the injected gas
to the arrangement direction (i.e., X-axis direction) is set such
that a gas injection range of the one-side upper injecting portions
53Aa' to 53Ad' is not overlapped with a gas injection range of the
other-side upper injecting portions 53Ae' to 53Ah'.
With this configuration, it is possible to securely prevent the gas
injected by the one-side upper injecting portions 53Aa' to 53Ad'
from colliding with the gas injected by the other-side upper
injecting portions 53Ae' to 53Ah'. As a result, since the gases are
not collided with each other, it is possible to prevent a wind
pressure from being decreased, and also prevent the cleaning liquid
from remaining on the outer peripheral surface of the third nozzle
313. Further, since a vortex flow of the gas can be formed within
the storage tank 51, it is possible to dry the outer peripheral
surface of the third nozzle 313 more efficiently.
Herein, there has been explained the example where the inclination
of the direction of the injected gas is set such that the gas
injection range of the one-side upper injecting portions 53Aa' to
53Ad' is not overlapped with the gas injection range of the
other-side upper injecting portions 53Ae' to 53Ah'. However, the
present disclosure is not limited thereto. The gas injection range
of the one-side upper injecting portions 53Aa' to 53Ad' may be
partially overlapped with the gas injection range of the other-side
upper injecting portions 53Ae' to 53Ah'. In this case, it is
possible to prevent the gases from colliding with each other by,
for example, arranging the one-side upper injecting portions 53Aa'
to 53Ad' not to directly face the other-side upper injecting
portions 53Ae' to 53Ah'.
Hereinafter, an arrangement of the lower injecting portion 53B will
be explained. As depicted in FIG. 8B, the gas injecting portion 53
includes five lower injecting portions 53Ba to 53Be. These lower
injecting portions 53Ba to 53Be are arranged in parallel to one
another at the one side of the storage tank 51, and configured to
inject the gas toward the other side of the storage tank 51.
As described above, the multiple lower injecting portions 53Ba to
53Be inject the gas (N.sub.2) toward the third nozzle 313 from the
one side of the third nozzle 313. Further, as described above, the
lower injecting portions 53Ba to 53Be located at the vertical
position substantially equal to the front end surface of the third
nozzle 313 is configured to inject the gas in a substantially
horizontal direction toward the front end surface thereof. For this
reason, if the lower injecting portions 53B are located at both
sides of the storage tank 51, there may be a collision between the
gases, so that the front end surface of the third nozzle 313 may
not be sufficiently dried.
Accordingly, in the nozzle cleaning device 50, the lower injecting
portions 53Ba to 53Be are located only at the one side of the inner
peripheral surface 61 of the storage tank 51, and, thus, the front
end surface of the third nozzle 313 can be dried efficiently.
Although there has been explained the example where the gas
injecting portion 53 includes the ten upper injecting portions 53Aa
to 53Aj and the five lower injecting portions 53Ba to 53Be, the
number of the upper injecting portions and the number of the lower
injecting portions are not limited to the above numbers.
Hereinafter, one of the upper injecting portions 53Aa to 53Aj will
be simply referred to "upper injecting portion 53A". Likewise, one
of the lower injecting portions 53Ba to 53Be will be simply
referred to as "lower injecting portion 53B".
Referring back to FIG. 5, the second cleaning unit 50B will be
explained. The overflow discharging portion 54 is configured to
discharge the cleaning liquid that overflows the storage tank 51 to
be collected in the liquid collecting portion 55.
As described above, since the second cleaning unit 50B includes the
overflow discharging portion 54, the cleaning liquid can be filled
to the top portion of the storage tank 51. Thus, it is possible to
easily clean the third nozzle 313 from the front end of the nozzle
313 to the upper part thereof.
Further, since a contaminant such as the cohesive material removed
from the third nozzle 313 can be discharged to the outside of the
storage tank 51 through the overflow discharging portion 54, it is
possible to prevent the contaminant removed from the third nozzle
313 from adhering again to the third nozzle 313.
Furthermore, since the overflow discharging portion is provided,
the cleaning liquid can be continuously supplied into the storage
tank 51, so that a vortex flow can be continuously formed within
the storage tank 51 during a cleaning process.
The liquid collecting portion 55 is provided below the storage tank
51 and the overflow discharging portion 54, and configured to
collect the cleaning liquid introduced from the storage tank 51
through the discharge opening 63 and the cleaning liquid introduced
from the overflow discharging portion 54.
The liquid collecting portion 55 is connected to the second drain
portion 44 (see FIG. 4) of the nozzle standby unit 40A via a valve
67. Thus, the cleaning liquid collected in the liquid collecting
portion 55 is drained to the outside through the valve 67 and the
second drain portion 44.
<Operation of Nozzle Cleaning Device>
Hereinafter, a nozzle cleaning process performed by using the
second cleaning unit 50B will be explained with reference to FIGS.
10A to 10E. FIGS. 10A to 10E are schematic side cross sectional
views each illustrating an operation example of the nozzle cleaning
process. Further, respective operations of the second cleaning unit
50B depicted in FIGS. 10A to 10E are controlled by the control unit
to be described later.
As depicted in FIG. 10A, before cleaning the third nozzle 313, the
second cleaning unit 50B performs a pre-process in which the HDIW
as the cleaning liquid is supplied into the storage tank 51 to be
stored therein.
In the pre-process, the control unit opens the valve 64 to supply
the HDIW as the cleaning liquid from the liquid discharging portion
52. Thus, the cleaning liquid is stored within the storage tank 51.
Further, the control unit opens the valve 67. Thus, the cleaning
liquid stored within the storage tank 51 and collected in the
liquid collecting portion 55 through the discharge opening 63 or
the overflow discharging portion 54 is drained to the outside from
the second drain portion 44 (see FIG. 4) of the nozzle standby unit
40A.
The control unit opens the first valve 65 before a level of the
cleaning liquid stored within the storage tank 51 reaches the
vertical position of the lower injecting portions 53B. Then, the
gas (N.sub.2) is injected from the upper injecting portions 53A and
the lower injecting portions 53B.
Thus, the nozzle cleaning device 50 can prevent the cleaning liquid
stored within the storage tank 51 from being introduced into flow
paths of the upper injecting portions 53A and the lower injecting
portions 53B. Further, a flow rate of the gas at the time of
opening the first valve 65 is required to prevent the cleaning
liquid stored within the storage tank 51 from being introduced into
the flow paths of the upper injecting portions 53A and the lower
injecting portions 53B.
After the cleaning liquid is discharged from the liquid discharging
portion 52 for a certain time, the control unit closes the valve
64. Thus, the discharge of the cleaning liquid from the liquid
discharging portion 52 is stopped, and the cleaning liquid stored
within the storage tank 51 is discharged through the discharge
opening 63. The control unit keeps the first valve 65 and the valve
67 open.
As described above, by performing the pre-process, the HDIW having
a lowered temperature and remaining within a line connecting the
supply source of the HDIW to the liquid discharging portion 52 can
be discharged, and the HDIW having a preset temperature can be
immediately discharged during the immersing and cleaning process to
be performed later. Further, the storage tank 51 gets warm since
the HDIW is stored in the storage tank 51 for a certain time.
Therefore, it is possible to suppress a decrease in a temperature
of the HDIW during the immersing and cleaning process.
After the cleaning liquid stored within the storage tank 51 is
drained out through the discharge opening 63, the control unit
operates the rotation elevating devices 33A to insert the third
nozzle 313 into the storage tank 51 (see FIG. 10B), and then,
performs the immersing and cleaning process as depicted in FIG.
10C.
Since the third nozzle 313 is inserted into the storage tank 51
after the cleaning liquid stored within the storage tank 51 is
drained out through the discharge opening 63, the insertion of the
third nozzle 313 does not cause the cleaning liquid to overflow the
storage tank 51 or to spatter.
As depicted in FIG. 10C, the control unit opens the valve 64 to
allow the liquid discharging portion 52 to discharge the HDIW as
the cleaning liquid. Thus, the cleaning liquid can be stored within
the storage tank 51 and a vortex flow revolving within the storage
tank 51 can be formed. As a result, the third nozzle 313 is
immersed in the cleaning liquid and the cohesive material of SPM is
removed.
As described above, the second cleaning unit 50B performs the
immersing and cleaning of the third nozzle 313. For this reason, a
cleaning process can be performed easily and uniformly as compared
with the conventional injecting and cleaning process. That is, an
uncleaned part of the nozzle 313 can be rarely seen.
Further, the second cleaning unit 50B forms the vortex flow of the
cleaning liquid within the storage tank 51 to clean the third
nozzle 313. Accordingly, it is possible to remove the cohesive
material of SPM adhering to the third nozzle 313 more
effectively.
As described above, the discharge opening 63 is positioned at the
substantially same axis as the central axis of the inner peripheral
surface 61 of the storage tank 51. Thus, the nozzle cleaning device
50 can allow a central position of a vortex formed at the time of
discharging the cleaning liquid through the discharge opening 63 to
be substantially the same as a central position of the vortex flow.
Therefore, it is possible to clean the third nozzle 313 more
efficiently by a synergy effect of the vortex flow and the
vortex.
Further, since the bottom surface 62 of the storage tank 51 has a
funnel shape, the vortex flow can be easily formed.
Furthermore, since the liquid discharging portion 52 is located at
the vertical position substantially equal to the front end surface
of the third nozzle 313, the vortex flow can be formed near the
front end surface of the third nozzle 313. As a result, it is
possible to effectively clean the front end surface to which the
cohesive material of SPM can easily adhere.
The cleaning liquid stored within the storage tank 51 is collected
in the liquid collecting portion 55 through the discharge opening
63 or the overflow discharging portion 54, and then, drained to the
outside from the liquid collecting portion 55.
The first valve 65 is kept open. For this reason, in the same
manner as the pre-process, since the gas is injected from the upper
injecting portions 53A and the lower injecting portions 53B, it is
possible to prevent the cleaning liquid from being introduced into
the flow paths of the upper injecting portions 53A and the lower
injecting portions 53B.
The control unit may open the second valve 66 together with the
first valve 65. Thus, a flow rate of the gas injected into the
storage tank 51 may be increased and the cleaning liquid stored
within the storage tank 51 makes bubbles. With the bubbles, it is
possible to clean the third nozzle 313 more effectively.
Accordingly, the second cleaning unit 50B may perform a bubbling
process in which after the cleaning liquid is stored to a vertical
position higher than the injection openings of the gas injecting
portion 53, the gas is injected from the gas injecting portion 53
(the upper injecting portions 53A and the lower injecting portions
53B) to make bubbles of the cleaning liquid.
After the cleaning liquid is discharged from the liquid discharging
portion 52 for a certain time, the control unit closes the valve
64. Thus, the discharge of the cleaning liquid from the liquid
discharging portion 52 is stopped, and then, the cleaning liquid
stored within the storage tank 51 is drained out through the
discharge opening 63. In this case, the cleaning liquid is
discharged to form a vortex flow. Therefore, it is possible to
reduce the amount of the cleaning liquid remaining on the outer
peripheral surface of the third nozzle 313, and also reduce a time
required for performing a drying process to be performed later.
Further, the control unit keeps the first valve 65 and the valve 67
open.
The second cleaning unit 50B repeatedly performs the
above-described immersing and cleaning process multiple times. To
be specific, after the control unit stops the discharge of the
cleaning liquid from the liquid discharging portion 52 and the
cleaning liquid within the storage tank 51 is drained, the cleaning
liquid is discharged again from the liquid discharging portion 52
to perform the immersing and cleaning process. Thus, it is possible
to clean the third nozzle 313 more effectively.
After the immersing and cleaning process is ended, the second
cleaning unit 50B performs the drying process in which the gas is
injected to the third nozzle 313 to dry the third nozzle 313 as
depicted in FIG. 10D.
In the drying process, the control unit opens the second valve 66
and allows the gas (N.sub.2) to be injected from the upper
injecting portions 53A and the lower injecting portions 53B at a
flow rate higher than that of the pre-process and that of the
immersing and cleaning process. As described above, the control
unit controls the first valve 65 and the second valve 66
(corresponding to the flow rate controller), so that the flow rate
of the gas injected from the gas injecting portion 53 can be set to
be different between the immersing and cleaning process and the
drying process.
The upper injecting portions 53A inject the gas toward the third
nozzle 313 from an upper portion of the front end surface of the
third nozzle 313 in the downwardly inclined direction. Thus, it is
possible to remove the cleaning liquid remaining on the outer
peripheral surface of the third nozzle 313 while preventing the
cleaning liquid from being scattered to the outside of the nozzle
cleaning device 50.
The lower injecting portions 53B inject the gas toward the front
end surface of the third nozzle 313 from the vertical position
substantially equal to the front end surface of the third nozzle
313 in the substantially horizontal direction. Thus, it is possible
to mainly dry the front end surface of the third nozzle 313 where
the cleaning liquid easily remains.
During the drying process, the control unit opens the valve 316 to
allow the third nozzle 313 to directly inject the gas (N.sub.2).
Since the gas is injected directly from the third nozzle 313, the
cleaning liquid introduced into the third nozzle 313 during the
immersing and cleaning process can be blown away to the
outside.
Further, the control unit may perform the above-described drying
process while moving the third nozzle 313 up and down. Thus, it is
possible to dry the third nozzle 313 more efficiently.
When a certain time passes after the drying process is started, the
control unit closes the second valve 66 and the valve 316. Thus,
the injection of the gas from the third nozzle 313 is stopped, and
the flow rate of the gas injected from the upper injecting portions
53A and the lower injecting portions 53B is reduced. Then, the
control unit closes the valve 67.
As depicted in FIG. 10E, the control unit operates the rotation
elevating devices 33A to move the third nozzle 313 into the second
accommodating portion 42 of the nozzle standby unit 40A. Then, the
nozzle cleaning process is ended.
When a series of substrate processes including a SPM process, a SC1
process, and a dual fluid process to be described later are ended,
the control unit closes the first valve 65 to stop the injection of
the gas from the upper injecting portions 53A and the lower
injecting portions 53B. Thus, it is possible to prevent the
cleaning liquid within the storage tank 51 from being scattered and
from adhering to the substrate W being processed.
<Another Configuration of Substrate Processing Apparatus>
Hereinafter, another configuration of the substrate processing
apparatus 1 will be explained with reference to FIGS. 11, 12A, and
12B. FIG. 11 is a schematic side cross sectional view illustrating
a configuration of the substrate processing apparatus 1. FIGS. 12A
and 12B are schematic side cross sectional views each illustrating
an operation example of a substrate process.
As depicted in FIG. 11, the substrate processing apparatus 1
includes a control unit 60, and respective operations of the
substrate holding unit 20, the processing liquid supplying units
30A and 30B, and the nozzle cleaning device 50 are controlled by
the control unit 60.
In the rotation holding device 21 of the substrate holding unit 20,
a circular ring-shaped table 21b is horizontally mounted on an
upper end of a hollow cylinder-shaped rotation shaft 21a. At a
periphery of the table 21b, multiple substrate holding bodies 21c
configured to be in contact with a periphery of the substrate W and
horizontally hold the substrate W are arranged at a interval along
a circumference thereof.
The rotation shaft 21a is connected to a rotation driving device
11. The rotation driving device 11 rotates the rotation shaft 21a
and the table 21b, and also rotates the substrate W held on the
table 21b by the substrate holding bodies 21c. The rotation driving
device 11 is connected to the control unit 60 and its operation is
controlled by the control unit 60.
In the substrate holding unit 20, an elevation shaft 21d is
inserted in a hollow portion at the center of the rotation shaft
21a and the table 21b to pass therethrough, and a circular
plate-shaped elevation plate 21e is mounted on an upper end of the
elevation shaft 21d. At a periphery of the elevation plate 21e,
multiple elevation pins 21f configured to be in contact with a
lower surface of the substrate W and elevate the substrate W are
arranged at a interval along the circumference thereof.
The elevation shaft 21d is connected to an elevation device 12, and
the elevation device 12 is configured to elevate the elevation
shaft 21d and the elevation plate 21e, so that the substrate W held
by the elevation pins 21f is also elevated. The elevation device 12
is connected to the control unit 60, and its operation is
controlled by the control unit 60.
The processing liquid supplying units 30A and 30B are provided
above the table 21b such that the arms 32A and 32B can be moved
horizontally. The arms 32A and 32B respectively include the
discharging devices 31A and 31B at the front ends thereof. Further,
the arms 32A and 32B respectively include the rotation elevating
devices 33A and 33B at the base ends thereof.
The rotation elevating devices 33A and 33B are connected to
rotation driving devices 13 and 14, respectively. The respective
rotation driving devices 13 and 14 horizontally move the arms 32A
and 32B and the discharging devices 31A and 31B between a standby
position outside the substrate W and a supply position above a
central portion of the substrate W. The rotation driving devices 13
and 14 are connected to the control unit 60 and their operations
are independently controlled by the control unit 60.
The first nozzle 312 of the processing liquid supplying unit 30A is
connected to a SPM supply source 91 via the valve 314. The third
nozzle 313 of the processing liquid supplying unit 30A is connected
to a processing liquid supply source 92 via the valve 315 and
connected to a gas supply source 93 via the valve 316. Further, the
second nozzle 317 of the processing liquid supplying unit 30B is
connected to a SC1 supply source 94 via the valve 318. These valves
314, 315, 316, and 318 are connected to the control unit 60, and
opening and closing thereof are independently controlled by the
control unit 60.
The processing liquid collecting device 22 of the substrate holding
unit 20 surrounds a lower part and an outer periphery of the
substrate W, and includes a collection cup 22a having an open top
above the substrate W. In the collection cup 22a, a collection
opening 22b is formed outside the outer periphery of the substrate
W. Further, a collection space 22c communicating with the
collection opening 22b is formed below the collection opening
22b.
Further, in the collection cup 22a, a concentric ring-shaped
partition wall 22d is provided at a bottom portion of the
collection space 22c, and configured to partition the bottom
portion of the collection space 22c into a first collection part
22e and a second collection part 22f in a concentric double ring
shape. At bottom portions of the first collection part 22e and the
second collection part 22f, multiple discharge openings 22g and 22h
are respectively are arranged at an interval along the
circumference. The respective discharge openings 22g and 22h are
connected to liquid drain lines (not illustrated) via suction
devices 15 and 16. Operations of the suction devices 15 and 16 are
independently controlled by the control unit 60.
Further, above the discharge openings 22g and 22h and in a middle
of the partition wall 22d within the collection cup 22a, multiple
gas exhaust openings 22i are formed at an interval along the
circumference. The gas exhaust openings 22i are connected to a gas
exhaust line (not illustrated) via a suction device 17. An
operation of the suction device 17 is controlled by the control
unit 60.
Further, right above the gas exhaust openings 22i and in the middle
of the partition wall 22d within the collection cup 22a, a fixed
cover 22j is provided with a space from the gas exhaust openings
22i. Above the fixed cover 22j, an elevation cup 221 is
provided.
The elevation cup 221 is connected to an elevation rod 22m that is
inserted in the partition wall 22d to pass therethrough and that
can be moved up and down. The elevation rod 22m is connected to a
cup elevating device 18. The elevation rod 22m is elevated by the
cup elevating device 18, and the elevation cup 221 is elevated
according to the elevation of the elevation rod 22m. The cup
elevating device 18 is connected to the control unit 60 and its
operation is controlled by the control unit 60.
At an upper end of the elevation cup 221, an inclined wall 22p,
inclined toward an inner upper area up to the collection opening
22b of the collection cup 22a, is provided. The inclined wall 22p
is extended in parallel to an inclined wall of the collection space
22c up to the collection opening 22b of the collection cup 22a to
be close to the inclined wall of the collection space 22c of the
collection cup 22a.
If the elevation cup 221 is moved downwards by the cup elevating
device 18, there is formed a flow path from the collection opening
22b to the discharge opening 22g of the first collection part 22e
between the inclined wall of the collection cup 22a and the
inclined wall 22p of the elevation cup 221 within the collection
space 22c (see FIG. 12A).
If the elevation cup 221 is moved upwards by the cup elevating
device 18, there is formed a flow path from the collection opening
22b to the discharge opening 22h at an inner space from the
inclined wall 22p of the elevation cup 221 within the collection
space 22c (see FIG. 12B).
Further, during a substrate process, the substrate processing
apparatus 1 elevates the elevation cup 221 of the processing liquid
collecting device 22 depending on a kind of the processing liquids
and discharges the processing liquid through one of the discharge
openings 22g and 22h.
By way of example, FIG. 12A illustrates an operation example of the
substrate processing apparatus 1 when the substrate W is processed
by discharging the SPM as an acid processing liquid to the
substrate W through the first nozzle 312. In the substrate
processing apparatus 1, while controlling the rotation driving
device 11 to rotate the table 21b of the substrate holding unit 20
at a preset rotational speed, the control unit 60 opens the valve
314. Thus, the SPM supplied from the SPM supply source 91 is
discharged to an upper surface of the substrate W through the first
nozzle 312.
Here, in the substrate processing apparatus 1, the control unit 60
controls the cup elevating device 18 to move the elevation cup 221
downwards. As a result, there is formed a flow path from the
collection opening 22b to the discharge opening 22g of the first
collection part 22e.
Thus, the SPM supplied to the substrate W is scattered toward the
outside of the outer periphery of the substrate W by a centrifugal
force caused by the rotation of the substrate W. Then, the SPM and
an atmosphere around the substrate W are collected by a suction
force of the suction device 15 from the collection opening 22b of
the collection cup 22a to the first collection part 22e of the
collection space 22c.
Further, FIG. 12B illustrates an operation example of the substrate
processing apparatus 1 when the substrate W is processed by
discharging the SC1 as an alkaline processing liquid to the
substrate W through the second nozzle 317. In the substrate
processing apparatus 1, while controlling the rotation driving
device 11 to rotate the table 21b of the substrate holding unit 20
at a preset rotational speed, the control unit 60 opens the valve
318. Thus, the SC1 supplied from the SC1 supply source 94 is
discharged to the upper surface of the substrate W through the
second nozzle 317.
Here, the substrate processing apparatus 1 controls the cup
elevating device 18 to move the elevation cup 221 upwards. As a
result, there is formed a flow path from the collection opening 22b
to the discharge opening 22h.
Thus, the SC1 supplied to the substrate W is scattered toward the
outside of the outer periphery of the substrate W by a centrifugal
force caused by the rotation of the substrate W. Then, the SC1 and
an atmosphere around the substrate W are collected by a suction
force of the suction device 15 from the collection opening 22b of
the collection cup 22a to the second collection part 22f of the
collection space 22c.
The substrate processing apparatus is configured as described
above. The substrate process and the nozzle cleaning process are
performed according to a substrate processing program stored in a
storage medium (not illustrated) readable by the control unit 60.
Further, if the storage medium can store various programs such as
the substrate processing program, it may be a semiconductor memory
type storage medium, such as a ROM or a RAM, or a disk type storage
medium, such as a hard disk or a CD-ROM.
<Timing for Performing Nozzle Cleaning Process>
Hereinafter, a timing for performing a substrate process and a
nozzle cleaning process will be explained. FIG. 13 shows a timing
for performing a substrate process and a nozzle cleaning
process.
In the substrate processing apparatus 1, the substrate W loaded
into the substrate processing apparatus 1 is held by the rotation
holding device 21 (see FIG. 1) and rotated at a preset rotational
speed. Then, as depicted in FIG. 13, in the substrate processing
apparatus 1, the discharging device 31A of the processing liquid
supplying unit 30A is located at the supply position above the
central portion of the substrate W and a SPM process is performed
by using the discharging device 31A. The SPM process is a substrate
process using the SPM discharged through the first nozzle 312 of
the discharging device 31A. During the SPM process, in the
substrate processing apparatus 1, the processing liquid supplying
unit 30B stands by at the nozzle standby unit 40B.
During the SPM process, the substrate processing apparatus 1
performs the pre-process explained with reference to FIG. 10A, so
that the HDIW having a lowered temperature and remaining within the
line is discharged and the storage tank 51 is warmed up. Thus, it
is possible to perform the immersing and cleaning process to be
performed later at an appropriate temperature.
Although the pre-process is performed during the SPM process
herein, the pre-process may be performed at any time between a time
when a series of the substrate processes are started and a time
when the immersing and cleaning process is started. By way of
example, the pre-process may be performed while or after the
substrate W is loaded into the substrate processing apparatus 1 or
may be performed after the SPM process is ended.
After the SPM process is ended, the substrate processing apparatus
1 moves the discharging device 31A from the supply position to the
nozzle cleaning device 50. Further, the substrate processing
apparatus 1 also moves the discharging device 31B of the processing
liquid supplying unit 30B from the nozzle standby unit 40B to the
supply position. Then, the substrate processing apparatus 1
performs a SC1 process by using the discharging device 31B. The SC1
process is a substrate process using the SC1 discharged through the
second nozzle 317 of the discharging device 31B.
During the SC1 process, the substrate processing apparatus 1
performs the nozzle cleaning process to clean the first nozzle 312
and the third nozzle 313 of the discharging device 31A moved to the
nozzle cleaning device 50.
As described above, the substrate processing apparatus 1 performs
the nozzle cleaning process onto the first nozzle 312 and the third
nozzle 313 during the substrate process (SC1 process) performed by
using the second nozzle 317. Thus, the substrate processing
apparatus 1 can clean the first nozzle 312 and the third nozzle 313
without stopping the series of the substrate processes.
Further, when the cleaning process onto the first nozzle 312 and
the third nozzle 313 during the substrate process is ended, the
substrate processing apparatus 1 moves the processing liquid
supplying unit 30A to the nozzle standby unit 40A to stand by at
the nozzle standby unit 40A.
After the SC1 process is ended, the substrate processing apparatus
1 moves the discharging device 31B from the supply position to the
nozzle standby unit 40B. Further, the substrate processing
apparatus 1 also moves the discharging device 31A, which has been
cleaned in the cleaning process, to the supply position again.
Then, the substrate processing apparatus 1 performs a dual fluid
process by using the discharging device 31A. The dual fluid process
is a substrate process using the processing liquid in a misty state
discharged through the third nozzle 313 of the discharging device
31A.
After the dual fluid process is ended, the substrate processing
apparatus 1 moves the discharging device 31A to the nozzle standby
unit 40A. Then, the substrate processing apparatus 1 increases the
rotational speed of the substrate W to perform a spin drying
process onto the substrate W. Thereafter, the substrate processing
apparatus 1 stops the rotation of the substrate W and ends the
series of the substrate processes.
As described above, the nozzle cleaning device 50 in accordance
with the first illustrative embodiment includes the storage tank
51, the liquid discharging portion 52, and the overflow discharging
portion 54. The storage tank 51 has the cylindrical inner
peripheral surface 61 and stores the cleaning liquid for cleaning
the nozzle (the first nozzle 312 or the third nozzle 313) used for
the substrate process. The liquid discharging portion 52 discharges
the cleaning liquid into the storage tank 51 toward a position
eccentric with respect to the central axis of the inner peripheral
surface 61 of the storage tank 51. Thus, the cleaning liquid is
stored within the storage tank 51 and a vortex flow revolving
within the storage tank 51 is formed. The overflow discharging
portion 54 discharges the cleaning liquid flowing over the storage
tank 51. Therefore, the substrate processing apparatus 1 in
accordance with the first illustrative embodiment uniformly cleans
the nozzle from the front end of the nozzle to the upper part
thereof.
Further, the substrate processing apparatus 1 in accordance with
the first illustrative embodiment includes the first nozzle 312;
the second nozzle 317 used for the substrate process performed
after the substrate process performed by using the first nozzle
312; and the third nozzle 313 used for the substrate process
performed after the substrate process performed by using the second
nozzle 317. The first nozzle 312 and the third nozzle 313 are
provided at the arm 32A (corresponding to a first arm) and the
second nozzle 317 is provided at the arm 32B (corresponding to a
second arm).
The substrate processing apparatus 1 performs the nozzle cleaning
process onto the first nozzle 312 and the third nozzle 313 during
the substrate process (SC1 process) performed by using the second
nozzle 317. Therefore, it is possible to clean the first nozzle 312
and the third nozzle 313 without stopping the series of the
substrate processes.
Furthermore, in accordance with the first illustrative embodiment,
there has been explained the example where the first nozzle 312 and
the third nozzle 313 are cleaned at the same time. However, the
substrate processing apparatus 1 may clean one of the first nozzle
312 and the third nozzle 313.
Moreover, in accordance with the first illustrative embodiment,
there has been explained the example where the first nozzle 312 and
the third nozzle 313 are provided at the arm 32A and the second
nozzle 317 is provided at the arm 32B in the substrate processing
apparatus 1. However, the present disclosure is not limited
thereto. In the substrate processing apparatus 1, each of the
nozzles used for the former and latter substrate processes may be
provided at each of the arms. Accordingly, during the substrate
process performed by using the nozzle provided at one of the arms,
the nozzle cleaning process may be performed onto the nozzle
provided at the other arms. As a result, it is possible to clean
the nozzle while preventing a time period required for the
substrate process from being increased.
In accordance with the first illustrative embodiment, there has
been explained the example where the third nozzle 313 is used as an
external mixed-type dual fluid nozzle. However, the third nozzle
313 may be used as an internal mixed-type dual fluid nozzle. The
internal mixed-type dual fluid nozzle mixes a liquid and a gas
within the nozzle, and then, discharges a mixed processing liquid
in a misty state through a discharge opening.
Second Illustrative Embodiment
However, during a nozzle cleaning process, a substrate process is
performed outside the nozzle cleaning device 50. For this reason,
it is desirable that a gas injected from the gas injecting portion
53 of the nozzle cleaning device is not leaked to the outside of
the nozzle cleaning device 50. Therefore, a nozzle cleaning device
may include an air intake unit configured to suction therein a gas
injected from a gas injecting portion. Hereinafter, an example of a
nozzle cleaning device including the air intake unit will be
explained with reference to FIG. 14.
FIG. 14 is a schematic perspective view of a configuration of a
nozzle cleaning device in accordance with a second illustrative
embodiment. Hereinafter, the same components as the above-described
components will be assign the same reference numerals and redundant
explanation thereof will be omitted.
By way of example, as depicted in FIG. 14, a nozzle cleaning device
50' may include a detachably attached air intake unit 70 above the
storage tank 51.
The air intake unit 70 includes a first air intake unit 71 and a
second air intake unit 72. The first air intake unit 71 is
positioned near a first cleaning unit 50A' and configured to mainly
suction therein a gas injected from a gas injecting portion of the
first cleaning unit 50A'. Further, the second air intake unit 72 is
positioned near a second cleaning unit 50B' and configured to
mainly suction therein a gas injected from a gas injecting portion
of the second cleaning unit 50B'.
Each of the first air intake unit 71 and the second air intake unit
72 includes multiple air intake openings 73. Further, the air
intake unit 70 includes air intake openings 74 near a position
where the arm 32A (see FIG. 2) is located during a nozzle cleaning
process. The air intake openings 73 and 74 communicate with each
other within the air intake unit 70, and are connected to a
non-illustrated air intake device via a line 75. The
non-illustrated air intake device is controlled by the control unit
60.
The air intake unit 70 suctions a gas through the air intake
openings 73 and 74 by an air intake force of the non-illustrated
air intake device. The amount of a gas taken by the air intake unit
70 is set to be greater than the amount of a gas injected from a
gas injecting portion of the nozzle cleaning device 50'. With this
air intake unit 70, the nozzle cleaning device 50' can prevent the
gas injected from the gas injecting portion from being leaked to
the outside of the nozzle cleaning device 50'.
As described above, the nozzle cleaning device 50' may be provided
above the storage tank and may include the air intake unit
configured to suction therein a gas whose amount is equal to or
greater than the amount of a gas injected from the gas injecting
portion.
Further, the nozzle cleaning device 50' includes a supplementary
air intake unit 56. In the nozzle cleaning device 50', by way of
example, if the amount of the gas suctioned by the air intake unit
70 is not sufficient, the supplementary air intake unit 56 may be
connected to the air intake device to perform an air intake process
through the supplementary air intake unit 56.
To be specific, the supplementary air intake unit 56 is connected
to a liquid collecting portion of the first cleaning unit 50A' and
a liquid collecting portion (see reference numeral 55 in FIG. 5) of
the second cleaning unit 50B'. By performing the air intake process
through the supplementary air intake unit 56, the gas injected to
the inside of the storage tank from the gas injecting portion may
pass through a discharge opening and the liquid collecting portion,
and then, may be suctioned to the outside from the supplementary
air intake unit 56.
The supplementary air intake unit 56 suctions therein the gas
injected from the gas injecting portion through the discharge
opening for discharging the cleaning liquid. That is, the discharge
opening for discharging the cleaning liquid also serves as a
suction opening for suctioning a gas. Accordingly, there is no need
to provide a suction opening for suctioning a gas in the storage
tank.
Further, the nozzle cleaning device 50' may perform the air intake
process by using only the supplementary air intake unit 56. In this
case, the supplementary air intake unit 56 suctions in a gas in an
amount equal to or greater than the amount of the gas injected from
the gas injecting portion.
Third Illustrative Embodiment
However, a configuration of the storage tank is not limited to the
example described in the first illustrative embodiment.
Hereinafter, another configuration example of the storage tank will
be explained with reference to FIGS. 15A and 15B. FIG. 15A is a
schematic side cross sectional view of a configuration of a storage
tank in accordance with a third illustrative embodiment and FIG.
15B is a schematic side cross sectional view of a first
modification example of the storage tank in accordance with the
third illustrative embodiment.
By way of example, as depicted in FIG. 15A, in a storage tank 51_1,
a vertex of a funnel-shaped bottom surface 62_1 may be located at a
position P2 eccentric with respect to a central axis P1 of the
inner peripheral surface 61. That is, a cleaning liquid discharge
opening 63_1 may be located at the position P2 eccentric with
respect to the central axis P1 of the inner peripheral surface
61.
Since the discharge opening 63_1 is located eccentrically with
respect to the central axis P1 of the inner peripheral surface 61,
a central position of a vortex formed when a cleaning liquid is
discharged through the discharge opening 63_1 becomes eccentric
with respect to the central axis P1 of the inner peripheral surface
61 of the storage tank 51_1. Thus, it is possible to prevent a dead
air space from being formed at the front end surface of the third
nozzle 313 and also possible to suppress non-uniformity in cleaning
of the front end surface of the third nozzle 313.
Further, as depicted in FIG. 15B, in a storage tank 51_2, a
partition member 57 extending toward the central axis P1 of the
inner peripheral surface 61 in a downwardly inclined direction may
be provided above the discharge opening 63_1 located eccentrically
with respect to the central axis P1 of the inner peripheral surface
61. Thus, it is possible to easily form a vortex flow of the
cleaning liquid while preventing a dead air space from being formed
at the front end surface of the third nozzle 313.
Further, in the first illustrative embodiment, although the
cylindrical inner peripheral surface 61 of the storage tank 51 is
formed in a circle shape (see FIG. 6) when viewed from the top, a
shape of the cylindrical inner peripheral surface of the storage
tank 51 when viewed from the top is not limited to the circle shape
and may be, for example, an elliptical shape horizontally extended
in a certain direction. Details thereof will be explained with
reference to FIGS. 16A to 16C.
FIG. 16A is a schematic plane cross sectional view of a second
modification example of the storage tank in accordance with the
third illustrative embodiment, FIG. 16B is a schematic side cross
sectional view of the storage tank depicted in FIG. 16A. FIG. 16C
is a schematic plane cross sectional view of a third modification
example of the storage tank in accordance with the third
illustrative embodiment.
As depicted in FIG. 16A, an inner peripheral surface 61_3 of a
storage tank 51_3 has a substantially elliptic shape when viewed
from the top. The third nozzle 313 is inserted into the storage
tank 51_3 while being close to a side of the storage tank 51_3.
Thus, as depicted in FIGS. 16A and 16B, a central axis P3 of the
inner peripheral surface 61_3 of the storage tank 51_3 may be
deviated from a central axis P4 of the third nozzle 313. That is,
since the third nozzle 313 may be located eccentrically with
respect to a central position of a vortex flow formed within the
storage tank 51_3, it is possible to prevent a dead air space from
being formed at the front end surface of the third nozzle 313.
Further, a cleaning liquid discharge opening 63_3 is located at a
position P5 opposite to the side of the third nozzle 313. Since a
central position of a vortex flow formed when a cleaning liquid is
discharged through the discharge opening 63_3 can be located
eccentrically with respect to the central axis of the third nozzle
313, it is possible to prevent a dead air space from being formed
at the front end surface of the third nozzle 313 more
effectively.
Herein, there has been explained the example where the inner
peripheral surface 61_3 of the storage tank 51_3 has a
substantially elliptical shape. However, the inner peripheral
surface of the storage tank may have a substantially rectangular
shape of which short sides are protruded in a circular arc shape as
depicted in FIG. 16C.
In the above-described illustrative embodiments, there has been
explained the example where a gas injecting portion has a two-stage
configuration including an upper injecting portion and a lower
injecting portion. However, the gas injecting portion may be a
one-stage configuration or may include discharging units in three
or more stages.
Further, in the above-described illustrative embodiments, there has
been explained the example where a substrate processing apparatus
includes a nozzle cleaning device configured to clean a first
nozzle and a third nozzle. However, the substrate processing
apparatus may further include a nozzle cleaning device configured
to clean a second nozzle. In this case, the nozzle cleaning device
for cleaning the second nozzle may be provided to be close to a
nozzle standby unit of the second nozzle.
Furthermore, in the above-described illustrative embodiments, a gas
injecting portion injects a gas during the pre-process or the
nozzle cleaning process, so that it is possible to prevent a
cleaning liquid stored in the storage tank from being introduced
into the flow path of the gas injecting portion. However, if the
cleaning liquid is not introduced into the flow path of the gas
injecting portion, the gas injecting portion does not need to
inject the gas. By way of example, by setting a diameter of the gas
injecting portion to be small enough not to introduce the cleaning
liquid, the introduction of the cleaning liquid into the flow path
of the gas injecting portion does not occur.
The above description of the illustrative embodiments is provided
for the purpose of illustration, and it would be understood by
those skilled in the art that various changes and modifications may
be made without changing technical conception and essential
features of the illustrative embodiments. Thus, it is clear that
the above-described illustrative embodiments are illustrative in
all aspects and do not limit the present disclosure. For example,
each component described to be of a single type can be implemented
in a distributed manner. Likewise, components described to be
distributed can be implemented in a combined manner. The scope of
the inventive concept is defined by the following claims and their
equivalents rather than by the detailed description of the
illustrative embodiments. It shall be understood that all
modifications and embodiments conceived from the meaning and scope
of the claims and their equivalents are included in the scope of
the inventive concept.
* * * * *